The invention relates to a system with virtual volume access and management.
Spiraling increases in processing capability have made computers indispensable in the modern world. Concurrently, information storage systems have become an important part of these computers to handle the resulting data explosion. Further, the need for a pervasive access to mission-critical data scattered among heterogeneous platforms has increased the complexity and cost of managing storage in corporate environments.
The storage and management of data have driven the development of new storage architecturesxe2x80x94Network Attached Storage (NAS) and Storage Area Network (SAN)xe2x80x94to meet growing storage demand.
In a NAS, intelligent storage devices connect directly to the network and are dedicated to one function: file serving. A NAS device lets administrators attach intelligent devices to networks, which are capable of directly retrieving and transmitting information to users. In general, a NAS product functions as a server in a client/server relationship. The NAS device has its own processor, a dedicated operating system or micro kernel, and processes file I/O protocols, such as NFS, to manage the transfer of data between itself and its clients. To applications running on the network, the NAS device appears to be a server. To a client, the NAS device is a large hard disk.
In a SAN environment, the function of storage is detached from network servers and centralized and managed as a separate network resource. SANs that are based on Fibre Channel buses have recently emerged as one high performance data communications environment available today to interconnect servers and storage. Running at Gigabit speeds and built on open standards, SANs offer better scalability, fault recovery and general manageability than conventional client-server LAN based approaches.
Although SANs may be connected together in a network, SANs are typically not network aware. As such, requesters such as servers can directly access drives attached to the SAN system. However, for accesses to remote drives attached to remote SANs, the requesters have to specifically direct their requests to the remote SANs using specialized drivers or code. As such, the software has to be customized to access remote data storage devices.
With the increasing demand for storage and continually lower prices of storage, system administrators are frequently facing the challenge of seamless expansion of online storage capacity. This requirement changes the dynamics of the way the data is stored on the disk or the tape and the way the reads and writes are done on the storage devices. Thus, users are demanding better ways of maintaining the data storage system and increasing storage performance and/or capacity to meet new demands.
In one aspect, a system manages storage space in one or more data storage devices by receiving a request for storage space from a requester, the request specifying one or more criteria associated with the requested storage space; searching a data structure such as a table containing attributes associated with the data storage devices; selecting one of the data storage devices whose attributes best match the one or more criteria; returning an identification associated with a portion of the selected data storage device to the requester; and creating a communication path between the requester and the selected data storage device.
Implementations of the invention may include one or more of the following. The searching step can be performed by an external manager. The attributes of a device can be statically configured in a server. The attributes of a device can be statically configured in a switch. Each data storage device can broadcast its attributes to a manager. The manager can store the attributes in the table, or can statically configures the attributes of a device. Each data storage device can broadcast value-added services associated with the data storage device to the manager. The manager can communicate using a Fibre Channel protocol. Further, each manager can manage one or more virtual volumes on each data storage device. The requester and the data storage devices can communicate using a network protocol. The network protocol can be an Internet Protocol (IP), an Asynchronous Transfer Mode (ATM) protocol, or an in-band control protocol which may be a Small Computer System Interface (SCSI) protocol. A server can manage the data storage device and can communicate using the Fibre Channel protocol. Alternatively, a switch can manages the data storage devices. The switch can communicate using the Fibre Channel protocol. The manager can communicate with other managers over a network. In this case, the searching step includes querying one or more tables in one or more remote storage area networks over the network; returning a remote identification associated with a portion of the selected data storage devices to the requester; and accessing the portion of the selected data storage device using the remote identification. The data storage devices may be a disk drive or a tape drive. The identification can a logical unit number. The requester can be a server or another manager. The method also includes performing manager operations to allocate space. The manager operations include one operation selected from a group of commands to initialize, attach, detach, connect, bind, write, read, move, signal, query, convert, control, and callback data in a storage partition.
In another aspect, a system for responding to a request for storage space includes one or more storage area networks (SANs); one or more data storage devices coupled to the one or more SANs; a requester coupled to one of the SANS; and a manager for supervising requests for storage space. The manager being operable to receive a request for storage space from a requester, the request specifying one or more criteria associated with the requested storage space; search a data structure containing attributes associated with the data storage devices; select one of the data storage devices whose attributes best match the one or more criteria; return an identification associated with a portion of the selected data storage devices to the requester; and create a communication path between the requester and the selected data storage device.
Implementations of the invention may include one or more of the following. One or more SANs can be interconnected over a network using a router. The manager can conform to a virtual volume management protocol. The manager can control one or more virtual partitions. Further, the manager can reside on a switch, which may be a Fibre Channel switch or a network switch. One or more of the data storage devices can be coupled to the requester over the SAN or connected over a local area network, a wide area network or a storage framework such as StoreX. The manager can allocate storage space using one or more commands selected from a group of commands to initialize, attach, detach, connect, bind, write, read, move, signal, query, convert, control, and callback data in a storage partition.
Advantages of the system includes the following. The total storage capacity of all data storage devices in a network can be tapped to satisfy each application""s requirements. Thus, dynamic redistribution of storage capacity among servers is possible without requiring any physical disk relocation or change in data protection characteristics. As a result, the invention provides quick and reliable access to and management of large amounts of information on-line.
The process of requesting storage space allocation is simple, and only requires a requester to submit to a SAN manager a request containing the requester""s desired storage space requirement. System specific details are hidden from the requester. Once the SAN manager assigns a data storage device matching the requester""s requirement, the requester directly communicates with its assigned data storage device. As such, high performance is achieved without overhead. In this manner, the invention provides a simple way to connect applications with an impromptu and expandable storage space.
Moreover, the resulting data storage system is simple to set up, expand, and manage. For instance, additional data storage devices may be easily added to without requiring a network administrator to load drivers and configure systems. The manager can be configured from a host processor, which provides a single point of administration for system utilities and tools, including monitoring and tuning software. As such, the invention supports enhanced system expansion, modularity, and configuration flexibility.
Other features and advantages will be apparent from the following description and the claims.